摘要
【目的】熔盐储热调峰调频是实现火电机组灵活性运行的重要手段,具有很好的应用前景。火电机组耦合熔盐储热系统的特性决定了火电机组的深度调峰水平、快速升负荷速率,也影响着火电机组灵活性运行的经济性,为提高调峰响应速度和系统安全性。【方法】本文梳理了熔盐储热系统设计原则、熔融盐的特性、汽轮机熔盐储热运行的限制、储放热过程及典型的工程示范项目,揭示了不同熔盐的应用特点。【结果】研究表明:(1)熔盐的安全运行温度决定了熔盐系统与火电机组的耦合方案,太阳盐和三元硝酸熔盐(HITEC盐)均能够实现深度调峰,但太阳盐无法利用蒸汽潜热;HITEC盐能够利用蒸汽潜热,但㶲损更高。(2)换热器夹点的存在决定于HITEC盐无法直接加热到最高完全运行温度,需要设置中温罐进行流量调节。(3)太阳盐最高安全运行温度略高于亚临界机组主蒸汽温度,因而可以直接将水和低参数蒸汽加热至主蒸汽/再热蒸汽温度,实现机组的快速爬坡。但对于超临界和超超临界机组,太阳盐最高安全运行温度是低于机组主蒸汽和再热蒸汽温度的。(4)太阳盐直接将给水加热至主蒸汽/再热蒸汽参数的汽化潜热阶段所需能量巨大,会产生非常大的㶲损,优化放热阶段抽取点从而降低汽化潜热阶段能够增加熔盐系统的往返效率。(5)目前工程示范表明,熔盐储热调峰是可行的,能够实现深度调峰和快速爬坡,在实现目标指标的前提下,增加系统的往返效率仍需要进一步研究。【结论】熔盐储热可有效提升火电机组灵活性,但需针对机组参数(亚临界/超临界)选择熔盐类型,并通过多热源协同、智能控制及低熔点熔盐开发进一步提高系统经济性与循环效率。
[Objective]Molten salt heat storage for peak load shaving and frequency adjustment is an important means to achieve flexible operation of coal-fired power plant.The coupling of coal-fired power plant with molten salt storage systems determines both the depth of peak load shaving and the load ramping speed,impacting the economic efficiency of coal-fired power plant.[Methods]Summarizing the related research progress in molten salt heat storage for peak load shaving and frequency adjustment is crucial for optimizing the coupling of molten salt systems with coal-fired power plant.[Results](1)The safe operating temperature of molten salt determines the coupling scheme with thermal power units.Both solar salt and HITEC salt can achieve deep peak shaving,but solar salt cannot utilize latent heat of steam;HITEC salt can utilize latent heat of steam but incurs higher exergy losses.(2)The existence of the heat exchanger pinch point means HITEC salt cannot directly heat to the highest operational temperature and requires a mid temperature tank for flow regulation.(3)The highest safe operating temperature of solar salt is slightly higher than the main steam temperature of subcritical units,allowing direct heating of water and low-parameter steam to main steam/reheat steam for fast ramping speed.However,for supercritical and ultra-supercritical units,the highest safe operating temperature of solar salt is lower than the main steam and reheat steam temperatures.(4)Solar salt requires a significant amount of energy to heat feedwater to main steam/reheat steam due to the large amount of the latent heat,leading to substantial losses.Optimizing the extraction location can reduce these losses and increase the round-trip efficiency of the molten salt system.(5)Current engineering demonstrations show that molten salt energy storage for peak shaving is feasible,achieving deep peak shaving and rapid ramp-up.However,further research is needed to increase the round-trip efficiency of the system.[Conclusion]Molten salt TES effectively enhances operational flexibility,yet salt selection must align with unit parameters(sub/supercritical).Future development should focus on multi-heat source synergy,intelligent control,and low-melting-point salts to improve economics and round-trip efficiency.
作者
丁天阳
陈辉
张超群
曹传胜
唐畅
姜聪
张扬
陈文
于洁
DING Tianyang;CHEN Hui;ZHANG Chaoqun;CAO Chuansheng;TANG Chang;JIANG Cong;ZHANG Yang;CHEN Wen;YU Jie;无(State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology,Wuhan 430074,Hubei China;China Energy Nanjing Electric Power Testing and Research Co.,Ltd,Nanjing 210046,Jiangsu China;China Energy Group New Energy Technology Research Institute Co.,Ltd,Beijing 102209,China;Hubei Electric Power Planning and Design Institute Co.,Ltd.,Wuhan 430040,Hubei China)
出处
《电力科技与环保》
2025年第4期528-541,共14页
Electric Power Technology and Environmental Protection
基金
湖北省中央引导地方科技发展项目(2024CSA088)
低碳智能燃煤发电与超净排放全国重点实验室开放课题(D2023FK091)。
关键词
熔盐
储热
调峰
火电机组
灵活性运行
molten salt
thermal energy storage
peak shaving
coal-fired power plant
flexible operation
